Surgical impactor-extractor appliance



United States Patent 3,541,868 SURGICAL IMPACTOR-EXTRACTOR APPLIANCE Robert M. Hall, 2084 Alisos Drive,

Santa Barbara, Calif. 93103 Filed Apr. 8, 1968, Ser. No. 719,424 Int. Cl. F16h 24/01; F1641 1/00 US. CI. 7444 3 Claims ABSTRACT OF THE DISCLOSURE A surgical appliance adapted to be applied to the output drive or spindle of a high speed surgical instrument to impart high speed reciprocal motion to the tool slide of the appliance to which is attached an impact hammer tool or extractor tool for use in surgical procedures.

BACKGROUND OF INVENTION This invention relates generally to appliance apparatus used in connection with the treatment and correction of abnormal bone conditions of the body including bone breakage and more particularly to appliances designed to be used in operative surgery wherein a reciprocal hammering or withdrawing forces is necessary in a surgical procedure to be performed.

DESCRIPTION OF PRIOR ART In many surgical procedures there is a necessity to use tools that are adapted to drive various surgical elements or fixtures into the body or to extract wires or other mechanical, surgical fixtures previously placed in the body, particularly where such elements are disposed in a bone structure. In the case of impaction driving in surgical procedures at the present time, a rubber headed mallet is used together with a metal impact driver in the form of a rod with flattened ends. Also a rubber headed mallet may be used in conjunction with a chisel in the preparation of areas of the bone structure of the human body for the insertion of various types of surgical fixtures. In other cases it becomes necessary during a surgical procedure to remove such surgical fixtures upon application of a withdrawing force applied by the surgeon.

On of the principal areas of surgical procedures wherein such appliances are used in orthopedic surgery. One of the principal orthopedic surgical procedures is the hip prosthesis replacement. A two piece appliance is used comprising a femoral component and an acetabular com- ;mnent. Impaction is needed to properly insert the femoral component into the femur bone after the femoral head has been removed. The femoral component in the past has been inserted into the femoral bone by the use of the mallet together with an impact driver consisting of a metal bar having a flat end to receive the continuous blows of the mallet and its other end adapted with an inwardly concave surface to be positioned on the ball head of the femoral component.

By the same token, there are orthopedic manually operated applicances adapted to remove the femoral component upon the application of manual reciprocal force with a suitable surgical driver to remove the prosthesis from the femoral bone. Such driver extractors are in the form of a long shaft with a handle at one end. Between the handle and the long shaft there is disposed a striking surface. The long shaft is inserted through a cannulated cylindrical member termed as a driving lug and an extractor hook is secured to the end of the shaft. By placing the extractor hook in hooked engagement with the orthopedic element to be removed from the body, such as a femoral prosthesis, the driver extractor ice is operated by reciprocal motion of the driving lug on the shaft of the extractor and continually driven against the striking surface of the handle. Thus the sliding or driving lug contacts the striking surface adjacent to handle of the driver extractor. An example of such a driver extractor now presently available for use in surgical procedures is the McReynolds Driver Extractor.

The disadvantage in the utilization of such manually operated orthopedic applicances for use in surgical procedures in the extraction and impaction of orthopedic fixtures to be, respectively, withdrawn from or placed into various bone structures of the body, is that the force applied by the surgeon is not of a uniform reciprocated action and the carelessness easily introduced in the operation of such tools may frequently permit the improper positioning of such orthopedic elements into the bone structure, for example, the femoral component into the femur bone.

SUMMARY OF INVENTION It is the principal aim of the present invention to provide a surgical appliance which may be adapted in the orthopedic field for applying uniform reciprocal motion in a surgical procedure where impaction or extraction forces are necessary.

The surgical impactor-extractor drive adapter or unit comprising the present invention is adapted to be driven by a high speed driven motor, preferably a pneumatically operated surgical instrument. The surgical impactorextractor drive adaptor is provided with a drive spindle supported on spaced antifrictional bearings mounted in the housing. The forward end of the spindle is provided with an eccentrically positioned crank arm which in turn is secured to a yoke member which provides reciprocal motion to an output shaft secured to the yoke and, thus, functions as a tool slide.

Although such reciprocal devices employing the general reciprocal principle disclosed in this application may be known, it is highly important in the surgical art that the transfer of driving force from the high speed rotary driving surgical instrument be done without excess vibration imparted to the impactor-extractor unit.

Thus, the present invention is specifically directed to a surgical impactor-extractor drive which is provided with a flexible sleeve coupling arrangement at its end adapted to receive the output drive shaft of a high speed rotary driving surgical instrument. The flexible sleeve coupling arrangement comprising this invention consists of a series of substantially cylindrical members provided with interconnecting lugs and notches in order to provide an arrangement wherein these members will be coaxially interlocked to the drive' spindle of the surgical impactorextractor drive unit but at the same time will not pass on to the rotary driven spindle undesirable lateral motions and vibrations which, for example, may be caused by a crooked or bent output shaft of the surgical driving instrument or misalignment On such an instrument caused from continuous use and wear when attached to the impactor-extractor drive unit.

Another feature of the present invention resides in the provision of a cap covering secured on the forward end of the housing of the surgical impactor-extractor drive unit which is adapted to be removed for servicing the impactor-extractor drive unit and at the same time remove the reciprocal tool slide from the eccentrically operated yoke. Upon securing the cap covering to the housing, the reciprocal tool slide may be readily attached again to the eccentrically operated yoke.

Other objects and advantages appear hereinafter in the following description and claims.

The accompanying drawings show for the purposes of exemplification, without limiting the invention or claims thereto certain practical embodiments illustrating the principles of this invention wherein:

FIG. 1 is a longitudinal cross-sectiona1 view of the surgical impactor-extractor drive unit comprising this in vention.

FIG. 2 is a front elevation of the surgical impactorextractor drive unit with parts in section.

FIG. 3 is a perspective view showing the flexible sleeve coupling arrangement of drive unit in exploded elevation.

FIG. 4 is a cross-sectional view of a mallet head adapter for securing to the tool slide of the surgical impactor-extractor drive unit.

FIG. 5 is a perspective view of an extractor hook adaptor for securing to the tool slide of the surgical impactorextractor drive unit.

Referring to FIG. 1 there is shown the surgical impactor-extractor drive unit 1 which comprises the housing 2. The end cover 3 is secured to the forward end of the housing 2 and is provided with an alignment pin 4 to properly position the end cover 3 relative to the housing 2. For this purpose the forward end face 5 of the housing 2 is provided with a hole 6 to receive the alignment pin 4.

The spindle 7 is supported within the housing 2 by means of the antifrictional bearings 8 and 16. The housing 2 is provided with a bore 11 having a step or shoulder 12 against which is seated the bearing as shown in FIG. 1. Bearing 10 is kept in its proper position on spindle 7 by means of the retaining ring 13.

The forward end of the spindle 7 is provided with the crank 14. As can be seen from FIG. 1, the crank 14 is offset from the rotary axis of the spindle 7.

The forward bearing 8 supporting the spindle 7 for rotation within the bore 11 is maintained in its proper seated position on the forward portion 15 of the spindle 7 and within the bearing retainer 9 by means of the shoulder 16 of the end cover 3. The bearing 8 may be press fitted within the retainer 9.

The crank arm 14 is adapted to receive the antifrictional bearing member 17 whose outer race 18 is provided with a shoulder area 20 to receive the yoke 21.

As shown in FIG. 2 the yoke 21 is provided with an extended portion 22 having an opening 23 to receive the pivot pin 24 which is press fitted into the opening 25 in the planar extension 31 of the cylindrical output shaft or tool slide 26. The tool slide 25 is supported in the bushing 27 which is housed within the annular portion 29 of the end cap or cover 3. The retainer 28 at the lower end of the end of the annular portion 29 maintains the bushing 27 in its proper position within the cylindrical bore 30.

As shown in FIG. 2 the end cover 3 is secured to the housing 2 by means of the long screws 32.

The lower end of the tool slide 26 is provided with a threaded lateral opening 33 to receive the screw 34. The screw 34 holds in secure position on the reciprocated tool slide 26 a surgical appliance to be used in a surgical procedure. Such a tool may be of the type as shown in FIG. 4 which comprises the mallet head 35 with the neck portion 36 to be received on the tool slide 26 therein which is secured thereto by tightening the screw 34 on the neck portion 36. The head 35 is also provided with a head member 37 which has a concave surface 38 adapted to be applied against the surface of the ball of a femoral component in a hip prosthesis to provide uniform reciprocal motion to the same when inserting the fenestrated intramedullary stern of the prosthesis into the femur bone. The head member 37 of the hammer 35 preferably consists of a softer material than metal such as nylon.

The tool slide 26 may be provided with the central bore 39 into which a tool may be inserted and secured into position by the screw 34.

In FIG. 5 there is shown an extractor hook 40 which has the extended portion 41 to be received within the bore 39 of the tool slide 26 and secured in position by the screw 34. The extractor hook 40 is provided with a hook member 42 which may be used in the orthopedic field in the removal of extraction of a femoral component in a hip prosthesis or the extraction of intramedullary pins.

From the foregoing it can be readily understood that the forces applied by the impactor-extractor drive unit 1 comprising this invention will be of much more uniform application than that found by the manually used driver extractors in the prior art. There is no possibility of improperly driving a member into a bone structure so that the surgeon at all times may maintain control of the surgical impactor-extractor unit in the proper application of impacting forces to an orthopedic element or the surgical fixtures. By the same token, the use of the impactorextractor drive unit comprising the present invention prevents distortion or bending of pins that are to be removed from bone structures of the body since the extraction force applied may be applied not only uniformly but also unidirectionally. The application of unidirectional force in the extraction or impaction of orthopedic elements is very diflicult in the use of manually operated driver extractors since both hands of the surgeon are necessary in the use of such manually operated appliances.

The rearward end of the housing 2 is provided with the abutment portion 43 which is divided into two sections by the slot 44. Lateral threaded opening 45 is provided through each of the divided sections or portions to receive the screw 46. Thus, the screw 46 is used as a means for tightening the rearward sleeve portion 47 of the housing 2 to the rotary driven surgical instrument to be secured to the impactor-extractor drive unit 1 and reciprocally drive the tool slide 26.

An important feature comprising the present invention resides in the flexible sleeve coupling arrangement shown in FIG. 3 as well as in FIG. 1. The flexible sleeve coupling arrangement comprises the drive adaptor 48, the drive sleeve 50 and the rearward end portion 51 of the spindle 7. The drive adaptor 48 is provided with a drive connection socket 52 which has at its bottom a key opening 53 to receive the alignment key on the forward end of the output spindle or shaft of the rotary driven surgical instrument. The rearward end 54 of the drive adaptor 48 is provided with two oppositely positioned lugs 55 which are adapted to be received in the notches 56 of the cylindrical drive sleeve 50. By the same token the cylindrical drive sleeve 50 is provided on its forward end 57 with a pair of oppositely disposed lugs 58 which are positioned in a plane substantially at right angles relative to a plane passing through the notches 56 of the cylindrical drive sleeve 50.

The extended portion 51 of the drive spindle 7 is in the form of a spindle coupling and is provided with two oppositely disposed outwardly open dents 60 and, thus, are adapted to receive the lugs 58 of the cylindrical drive sleeve 50. The extended portion 51 comprises the cylindrical wall section 61 which houses the cylindrical drive sleeve 50, with the lugs 58 of the drive sleeve 58 resting on the shoulder 62 within the extended portion 51 of the spindle 7. The coaxial chamber 63 is provided to receive the forward cylindrical section 64 of the drive adaptor 48. Thus, it can be seen that upon assembling the drive adaptor 48 within the drive sleeve 50 and thence the assembled drive adaptor-drive sleeve arrangement within the extended portion 51 of the spindle 7, the lugs 55 of the drive adaptor 48 will be substantially in alignment with the shoulder 65 of the annular slot 67 of cylindrical wall section 61.

The unique feature of the flexible sleeve coupling arrangement as shown in FIG. 3 is that the drive sleeve 50 permits a flexible connection between the drive adaptor 48 housing the drive connection socket 52 for receiving the output shaft or spindle of a surgical rotary driven instrument and the extended portion 51 of the spindle 7 of the impactor-extractor drive 1. Although there may be present undesirable lateral forces caused by the surgical instrument driving the impactor-extractor drive unit 1, for example, an output shaft on the instrument such wobble motion or lateral forces derived from such motion are absorbed in the loose flexible arrangement brought about by the interconnecting coupling arrangement and particularly by the drive sleeve 50.

The retaining ring 66 retains the drive adaptor 48 and drive sleeve 50- in their proper driving relationship with the extended portion 51 of the spindle 7. The retaining ring 66 is provided to be secured within the annular slot 67 adjacent the shoulder 65 on the inner surface 68 of the cylindrical wall section 61. The drive adaptor 48 and the drive sleeve 50 are held within the chamber of the extended portion 51 in a direct connected driving relationship which provides, at the same time, a loose coupling to permit lateral movement of these parts relative to the spindle 7.

I claim:

1. A surgical impactor-extractor drive unit including a housing with a stepped bore, spaced antifrictional bearings mounted in said bore supporting a spindle, a crank on one end of said spindle adjacent one of said bearings, an open ended coaxial chamber at the opposite end of said spindle having outwardly open dents, a drive adaptor for insertion in said coaxial chamber and having a drive connection socket to receive the output of a rotary power tool, outwardly extending lugs on said drive adaptor, and

a cylindrical drive sleeve having lugs to fit said open dents and notches to receive said drive adaptor lugs to coaxially interlock said spindle and said drive adaptor.

2. A surgical impactor-extractor drive unit including a housing containing spaced antifrictional bearings supporting a spindle having a drive socket on one end and a crank extending from the other end of said spindle, a cap covering said crank and secured to said housing, a sleeve bearing in said cap having its axis at right angles to said crank, a tool slide having pivot means connecting with said crank and fastening means for securing said cap to said housing and retaining said tool slide pivoted to said crank.

3. The surgical impactor-extractor drive unit of claim 2 characterized in that said pivot means includes a yoke mounted on an antifrictional bearing fitted on said crank, and a pivot pin secured to said yoke and journaled in said tool slide.

References Cited UNITED STATES PATENTS 1,459,035 '6/ 1923 Raisig 646 2,503,907 4/1950 Hefler 7444 2,630,852 3/1953 Myers 7444 2,767,564 10/1956 Green 646 WESLEY S. RATLIFF, JR., Primary Examiner US. Cl. X.R. 648 

